1. Field
The present application relates generally to the operation and design of radio frequency transceivers, and more particularly, to a system for I-Q phase mismatch detection and correction.
2. Background
High quality signal transmission and reception is especially important in portable devices. Typically, such devices include a local oscillator (LO) to generate in-phase (I) and quadrature phase (Q) signals that are designed to have a phase relationship of 90 degrees.
One problem associated with the generation of I and Q signals is I/Q mismatch, which can cause a residual side tone. There are two main types of I/Q mismatch. One is an amplitude mismatch of the I/Q signals and the second is a phase mismatch of the I/Q signals. In general, LO generated I/Q signals are less sensitive to amplitude mismatch, since the LO I/Q signals have full supply swing levels. However, the LO I/Q signals are very sensitive to I/Q phase mismatches especially in divide-by-2 LO generation architectures.
Therefore, it would be desirable to have a system that can continuously detect and correct I/Q phase mismatches in a transceiver.